Properties of the Number 21439

Twenty-One Thousand Four Hundred Thirty-Nine

Basics

Value: 21438 → 21439 → 21440

Parity: odd

Prime: No

Previous Prime: 21433

Next Prime: 21467

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 11 × 1949

Divisors: 1, 11, 1949, 21439

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001110111111

Octal: 51677

Duodecimal: 104A7

Hexadecimal: 53bf

Square: 459630721

Square Root: 146.42062696218727

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Numbers k that are the products of two distinct primes such that 2·k-1, 4·k-3, 8·k-7, 16·k-15 and 32·k-31 are also products of two distinct primes. A177214

Number of Van Lier sequences of length n. A5272

Numbers k that are the products of two distinct primes such that 2·k-1, 4·k-3, 8·k-7, 16·k-15, 32·k-31 and 64·k-63 are also products of two distinct primes. A177215

Crystal ball sequence for diamond. A7904

Composite numbers n such that σ(n+24) = σ(n) + 24. A54983

a(n) = 4·n³ - 18·n² + 27·n - 12. A271828

Number of minors in the n-sunlet graph. A354671

a(n) = coefficient of xⁿ in A(x) such that x = ∑_n=-oo..+oo xⁿ * (1 - xⁿ/A(-x))ⁿ. A360233

G.f. A(x) satisfies x = ∏_n>=1 (1 - xⁿ*A(x)) * (1 - x^n-1/A(x)) * (1 + xⁿ). A384269

Numbers n such that n contains exactly 5 digits, all distinct, and n² contains exactly 9 distinct digits. A204691